DE3707280A1 - METHOD AND DEVICE FOR STORAGE - Google Patents

Description

The invention relates to a new storage method using a liquid crystal as well to a new storage facility.

Storage devices, such as magnetic devices Use means or record carriers, facilities, which take advantage of a photomagnetic effect, semiconductor memories, etc. are already known. Any of these conventional However, facilities are relatively under construction complicated and laborious to manufacture. Furthermore point these facilities have drawbacks in that they can be influenced by electromagnetic interference.

The invention is accordingly based on the object To create storage device that is largely free of is electromagnetic interference.

Furthermore, a storage device of relatively simple Structure to be created.

The above problem is solved by the invention covered in the claims.

According to the present invention, a voltage of more than 0.7 V to a liquid crystalline viologen created to change its electrical conductivity, and the resulting state of the viology, in which  the electrical conductivity has been changed exploited as a saved state.

A storage device according to the present invention includes a pair of electrodes between which a liquid crystalline viologen is arranged. Furthermore, the electrodes are writing and reading devices electrically connected.

The invention is illustrated below with the aid of drawings for example explained in more detail.

Fig. 1 shows a sectional view of a memory device according to an embodiment of the invention.

FIG. 2 illustrates in a diagram the changes in the electrical conductivity of a liquid-crystalline viologen with respect to the applied voltages and as a function of times given in hours.

First, a memory device according to the invention will be described with reference to FIG. 1.

A pair of electrodes 20 and 21 are formed on two base plates 10 and 11 , respectively. Although base plates are not always required, glass plates or monocrystalline silicon plates with electrically conductive oxide layers thereon can be used as electrodes 20 and 21 , such as Nesa glass, when used. Of course, metal can be used for the electrodes 20 and 21 .

The electrodes 20 and 21 are arranged parallel to one another; an annular insulation spacer 3 is provided between the electrodes, which consists, for example, of Teflon (trade name). The interior delimited by the electrodes 20 and 21 and the spacer 3 is filled with a liquid crystalline viologen 4 . The distance between the electrodes 20 and 21 is, for example, 120 μm.

The electrodes 20 and 21 are connected to a voltage supply source 6 via a switch 5 which operates in accordance with the device. For example, if the device in an electrical machine is used to store an occurrence or the duration of the power supply failure, the switch 5 is closed only during the power supply failure. If the device for storing the magnitude of the applied voltage is used, a voltage supply generator to be measured is connected to the electrodes 20 and 21 via the switch 5 or directly instead of the voltage supply source 6 .

The electrodes 20 and 21 are connected to a detector circuit 7 which determines the state of the liquid-crystalline viologens 4 , for example its specific resistance. Based on the determination, a message can be displayed on a control panel (not shown).

The liquid crystalline viologen 4 is preferably a viologen halide (a compound of N-substituted dipyridyl). For example, N, N′-bis (3,6,9-trioxatridecyl) -4,4′-dipyridinium dÿodide, N, N′-bis (3,6,9,12-tetraoxadecyl) -4,4′- Dipyridinium Dÿodid, N, N'-bis (3,6,9-trioxatridecyl) - 4,4'-dipyridinium dibromide or the like is used.

Viologen used in the present invention has to show liquid crystalline properties. Viologen without liquid crystalline properties  useless because its electrical conductivity is too does not change when a voltage is applied, or there despite changing electrical conductivity the changed conductivity state is not maintained can be.

In the present invention, the term "liquid crystalline" used in the meaning that not just a liquid crystalline state in its original Meaning is grasped, but also that a sintered state is covered in which the liquid crystalline Properties are retained.

Below are embodiments of the invention explained.

example 1

A storage device, as shown in FIG. 1, was produced using N, N′-bis (3,6,9-trioxatridecyl) -4,4′-dipyridinium dÿodide as liquid crystalline viologen 4 , which had the following structural formula:

This connection can be established, for example be that one mole of 4,4'-dipyridyl and two moles of 3,6,9- Trioxatridecyl iodide were dissolved in acetonitrile to react at 80 ° C for 24 hours.

The transition of this connection from the solid state into the smectically liquid crystalline state higher Order generally takes place at 43 ° C. In the event that the Compound from the liquid crystalline state in the solid state in a process with sinking Temperature reconstituted, and then again from  liquid state in the liquid crystalline state the last mentioned transition took place at 25 ° C. In contrast, the transition from liquid crystalline state in the solid state at 18 ° C without reference to its hysteresis. The Transition between the liquid crystalline state and the melting state occurs at 219 ° C.

When the switch 5 of the memory device shown in FIG. 1 was closed in order to apply a voltage of 30 V for a period of 2.6 minutes from the voltage supply source 6 to the liquid crystalline viologen 4 , its specific resistance changed from 2 × 10 ⁷ Ohm · cm to 1 × 10 ³ Ohm cm, ie more than 10 ⁴ times. The temperature of the liquid crystalline violog 4 was 110 ° C. when the voltage was applied, and the viologen showed sufficient liquid crystalline properties.

After the voltage supply ended, the memory device retained although they are at room temperature for three days has been left in an argon atmosphere for a long time State of high conductivity where the specific Resistance was or is low.

If the level of the applied voltage is varied, relationships become apparent between the application time and the change in the electrical conductivity σ of the storage device, as illustrated in FIG. 2. As is apparent from Fig. 2, if a voltage of more than 0.7 V is applied, the electrical conductivity of the device will increase in accordance with the application time. Particularly when a voltage of more than 5 V is applied, the electrical conductivity changes enormously within a relatively short period of time.

Therefore, the following uses for the storage device expected.

First, the facility between the state low conductivity and the state of high conductivity changed by a voltage pulse of more than 5 V, preferably with more than 30 V, is applied; it is determined if the facility is in good condition low conductivity or high conductivity. This storage method is a digital storage method.

Second, a constant voltage below 5 V, preferably close to 1 V, applied to the device, and the change in electrical conductivity will measured to determine the voltage application time. In this case, even if the voltage is discontinuous is fed, the total berthing time the voltage can be determined.

The voltage values required in the above methods are independent of the thickness of the liquid-crystalline violog 4 .

The specific resistance of 2 × 10 ⁷ ohm cm of this material (1) without the electrical stimulus described above is extremely high; it is of a value similar to, for example, the specific resistance of 10 ⁹ ohm.cm (50-90 ° C.) to 10 ⁵ ohm.cm (70-130 ° C.) of quaternary ammonium salt of long-chain alkyldiazo-bicyclo [2,2,2 ] Octane halide, which is known as an ionic conductor. Even if the material (1) is in the smectically liquid crystalline state with high viscosity, the material has such a high electrical resistance in the case that the above-described electrical stimulus is not applied.

In the solid state, ie in the state in which the transition to the liquid-crystalline state due to heat has not occurred, an electrical stimulus similar to that in the liquid-crystalline state described above does not cause any reduction in the electrical resistance on this material (1). The specific resistance of this material at 25 to 30 ° C is, for example, almost 10 ¹¹ Ohm · cm, which is an extremely high value. Even if an electrical stimulus of 0 to 30 V were applied to this material, there would be no decrease in specific resistance as a whole.

In contrast, in the sintered state, in which the liquid crystalline properties are retained, an electrical stimulus similar to the one above described liquid crystalline state noticeable decrease in electrical resistance, and similar to that of the liquid crystalline Status. It is also compared to the liquid crystalline State the required amount of time to achieve the same or similar value of electrical Resistance in short, which results in good behavior.

In the storage device shown in FIG. 1, the liquid crystalline viologen 4 can be formed by pressure molding with the electrodes 20 and 21 . Alternatively, the viologen may be formed by any known molding or casting process, such as an application process, a casting process, a dispersant mixture process, a vacuum evaporation process, and an electrochemical process.

In one embodiment of the application process, a chloroform solution of Compound (1) described above was applied to gold electrodes, each having a thickness of 2000 Å, the length being 2 mm and the width 20 µm. The device was formed on a substrate made of monocrystalline silicon. The gap between the electrodes was 10 µm. When a 1 V electrical stimulus was applied to this device at 110 ° C for two minutes, the electrical resistance decreased from 10 ⁶ Ohm · cm to about 5 × 10 ³ Ohm · cm, ie the electrical conductivity of the material increased about two hundred times.

When this storage device was modified each of the electrodes, between which a liquid crystalline Viologist was layered from one Matrix of needle electrodes, with only one desired Patterns of the needle electrodes controlled in this way was or will be that the electrical resistance only the desired pattern of the liquid crystalline Viologens decreased. This facility can be used as electrical connector used to connect only possible in a certain pattern.

Example 2

N, N′-bis (3,6,9-trioxatridecyl) -4,4′-dipyridinium dibromide with the following structural formula was used:

This compound is liquid crystalline from room temperature to 200 ° C (decay). The stable liquid crystal of this material was sandwiched between two transparent electrodes with a 0.1 mm Teflon spacer so that the electrical conductivity was measured. When a voltage of 30 V is applied at 110 ° C, the electrical conductivity increases from 5 × 10 ^-9 Ohm ^-1 cm ^-1 to about 10 ^-5 Ohm ^-1 cm ^-1 .

Each transparent electrode consisted of 95% In ₂ O ₃ and 5% SnO ₂ ; it had a surface resistance of 10 ohms.

The electrical conductivity was measured as follows. The device was placed in a measuring cell which was decompressed for two hours (up to 0.1 mmHg in liquid N ₂ ). The atmosphere in the measuring cell was then replaced by argon gas dried with P ₂ O ₂ and the device was then exposed to the presence of P ₂ O ₂ for 2.5 hours (vapor pressure 2 × 10 ^-5 mg / l). The device was heated to a constant temperature by means of a hot plate at 110 ° C., and the voltage values and the current values were recorded at various points between 1 V and 100 V.

The electrical conductivity σ was calculated according to the following equation (in the same way this applies to example 1 and the following comparative examples 1 to 3): σ : electrical conductivity (Ohm ^-1 cm ^-1 )
I : current (A)
l : thickness of the sample (cm)
V : voltage (V)
A : area of the sample (cm ² )

Comparative Example 1

A device similar to that of Example 2 was made using the following material:

Since this material was not liquid, but solid, a sample of this material was turned into a tablet with a thickness of 0.17 to 0.19 mm and an area of about 2 in a tablet press machine at a pressure of 400 kg / cm ² for five minutes mm × 2 mm pressed. The tablet was layered together by two transparent electrodes with a 0.1 mm Teflon spacer and the device in question was fixed on a hot plate with clips.

Although the electrical conductivity σ was measured in a similar manner as in Example 2, it showed no significant change, even when an electrical stimulus was applied (132 ° C: 1 × 10 ^-10 to 3 × 10 ^-11 ohms ^-1 cm ^-1 ).

Comparative Example 2

Similar to Comparative Example 1, a tablet was made using the following material:

The tablet or pellet was made using two transparent electrodes similar to Comparative Example 1 arranged in a layered construction.

The temperature was kept at 30 ° C and the current was measured at a voltage of 10 V; this resulted in approximately 100 pA ( σ = 5 × 10 ^-12 Ohm ^-1 cm ^-1 ). Corresponding measurements were carried out at various points up to 150 ° C. The result is summarized in Table 1 below. No change in the electrical conductivity of the electrical stimulus was observed.

Table 1

Comparative Example 3

According to Comparative Example 2, a tablet or pellet was produced using the following material:

This material was solid at 132 ° C.

The measurements were taken at fixed temperatures of 26 ° C and 110 ° C at a voltage of 30 V. There was no change in electrical Conductivity observed due to an electrical stimulus.

Table 2

Claims (12)

1. A method of storage, characterized in that a voltage of more than 0.7 V is applied to a viologen, which shows liquid crystalline properties, in such a way that the electrical conductivity of the viologen in question is changed, and that the resulting state of the viologens, in which the electrical conductivity has been changed is used as a stored state. 2. The method according to claim 1, characterized in that that electrical conductivity of the viologens between the lower state Conductivity and the state of strong conductivity greatly changed with a voltage of more than 5 V. becomes and that it is determined whether the viologen is in the Low conductivity state or strong state Conductivity.   3. The method according to claim 1, characterized in that a tension between 0.7 V and 5 V is applied to the viologen and that then the extent of the change in electrical Conductivity of the viologens is measured to determine how long the mentioned tension on the viologen was created. 4. The method according to claim 1, characterized in that as a viologist a Halide is used. 5. The method according to claim 4, characterized in that as a viologist a matter is used, which consists of N, N'-bis (3,6,9-trioxatridecyl) - 4,4′-dipyridinium dÿodid, N, N′-bis (3,6,9,12-tetraoxadecyl) - 4,4′-dipyridinium dÿodide and N, N′-bis (3,6,9- Trioxatridecyl) -4,4'-dipyridine dibromide is selected. 6. The method according to claim 1, characterized in that viologen is used, which in its original meaning is liquid is crystalline state. 7. The method according to claim 1, characterized in that viologen in the sintered state is used in which the liquid crystalline Properties are retained. 8. Storage device, in particular for performing the method according to one of claims 1 to 7, characterized in that a pair of electrodes ( 20, 21 ) is provided, between which a liquid crystalline properties showing viologen ( 4 ) is arranged that with the electrodes a supply source ( 6 ) is connected, which supplies a voltage to the viologen, and that a detector device ( 7 ) is connected to the electrodes, with the aid of which the state of the electrical conductivity of the viologens can be determined. 9. Storage device according to claim 8, characterized characterized that the viologen a Viologen halide is. 10. Storage device according to claim 9, characterized characterized that the viologen from N, N′-bis (3,6,9-trioxatridecyl) -4,4′-dipyridinium dÿodide, N, N′-bis (3,6,9,12-tetraoxadecyl) -4,4′-dipyridinium dÿodide and N, N'-bis (3,6,9-trioxatridecyl) -4,4'-dipyridinium Dibromide is selected. 11. Storage device according to claim 8, characterized characterized that they are for storage an occurrence or the duration of a supply voltage failure serves in an electrical machine and that a tension on the viologen from the Supply source only during the failure of the Power supply is supplied. 12. Storage device according to claim 8, characterized characterized that they are for storage the size of a voltage supplied and that with a voltage supply source to be measured connected is.